Fix complaints from Go Report Card

[jonashelgemo]

Forwardlytics gets an A+, but there are some minor issues that should probably be fixed: https://goreportcard.com/report/github.com/jipiboily/forwardlytics

[jipiboily]

Good to know, thanks @helgeblod!

[jonashelgemo]

I have fixed all the issues in my fork of forwardlytics (jonashelgemo@8136cf8, https://goreportcard.com/report/github.com/helgeblod/forwardlytics). I can submit a pull-request as soon as #51 is merged. Cool?